Semiconductor memory devices are divided into volatile memory devices and non-volatile memory devices. Volatile memory devices lose their stored data when there is no power supplied to the memory device. Representative volatile memory devices are Dynamic Random Access Memory (DRAM) devices and Static Random Access Memory (SRAM) devices. Non-volatile memory devices retain their stored data even when there is no power supplied to the memory device. Due to these characteristics, the non-volatile memory devices may be used as storage media loaded in portable and/or electronic products.
As semiconductor industries have been highly developed, various characteristic enhancements of the non-volatile memory devices have become desirable. Data stored in the non-volatile memory devices may be damaged due to various external and/or internal factors. Losing data in the non-volatile memory devices may cause errors in the functionality of the device. Currently, since the demand for highly developed semiconductor devices is constantly increasing, developers are actively researching methods to improve various characteristics of the non-volatile memory devices.